The objective of this proposal is to test the hypothesis that loss of A-regulated AR function is the molecular basis for the development of A-independent prostate cancer that contributes to the deregulated expression of prostate cancer genes. It is proposed that other mediators, such as the growth factors IGF-I, EGF, and KGF, mediate A-independent pathways via ligand independent activation of AR. To test these hypotheses, the frequency and nature of AR mutations in primary and metastatic prostate cancers will be determined in a transgenic mouse model. AR mutations will be identified using SSCP and the functional effects of the mutations determined in DNA mobility shift assays using the probasin ARE. Transient transfection studies using cell lines derived from the SV40 derived prostate tumor cell lines and the probasin promoter-CAT reporter vector are planned. The ability of specific AR mutations to confer dominant growth and metastatic advantage will be determined using stable transfection in immortalized tumorigenic and non-metastatic TRAMP-C cell lines with subsequent grafting to syngeneic mice. The temporal and spatial pattern of gene expression associated with progression and metastasis of prostate cancer will be determined.